Field & Type Operations

/**
 * Collect fields from a selection set, handling fragments and inline fragments
 * @param schema - The GraphQL schema
 * @param fragments - Map of fragment definitions
 * @param variableValues - Variable values for the request
 * @param runtimeType - The runtime object type
 * @param selectionSet - The selection set to collect from
 * @returns Collected fields and patches
 */
function collectFields(
  schema: GraphQLSchema,
  fragments: Record<string, FragmentDefinitionNode>,
  variableValues: Record<string, any>,
  runtimeType: GraphQLObjectType,
  selectionSet: SelectionSetNode
): FieldsAndPatches;

/**
 * Collect subfields from a field's selection set
 * @param schema - The GraphQL schema
 * @param fragments - Map of fragment definitions
 * @param variableValues - Variable values for the request
 * @param returnType - The return type of the field
 * @param fieldNode - The field node containing the selection set
 * @returns Collected subfields and patches
 */
function collectSubfields(
  schema: GraphQLSchema,
  fragments: Record<string, FragmentDefinitionNode>,
  variableValues: Record<string, any>,
  returnType: GraphQLOutputType,
  fieldNode: FieldNode
): FieldsAndPatches;

interface FieldsAndPatches {
  fields: Record<string, FieldNode[]>;
  patches: PatchFields[];
}

interface PatchFields {
  label: string;
  fields: Record<string, FieldNode[]>;
}

import { collectFields, collectSubfields } from "@graphql-tools/utils";

// Collect fields during execution
const resolveUser = (source, args, context, info) => {
  const { fields } = collectFields(
    info.schema,
    info.fragments,
    info.variableValues,
    info.returnType,
    info.fieldNodes[0].selectionSet
  );
  
  // Optimize database query based on selected fields
  const selectedFields = Object.keys(fields);
  const user = fetchUserWithFields(args.id, selectedFields);
  
  return user;
};

// Collect subfields for nested resolution
const resolveUserPosts = (user, args, context, info) => {
  const postType = info.schema.getType('Post') as GraphQLObjectType;
  const { fields: subfields } = collectSubfields(
    info.schema,
    info.fragments,
    info.variableValues,
    postType,
    info.fieldNodes[0]
  );
  
  return fetchPostsWithFields(user.id, Object.keys(subfields));
};

/**
 * Iterate over all fields in a GraphQL schema
 * @param schema - The schema to iterate over
 * @param fn - Function called for each field
 */
function forEachField(schema: GraphQLSchema, fn: FieldIteratorFn): void;

/**
 * Iterate over all default values in a GraphQL schema
 * @param schema - The schema to iterate over
 * @param fn - Function called for each default value
 */
function forEachDefaultValue(schema: GraphQLSchema, fn: DefaultValueIteratorFn): void;

type FieldIteratorFn = (
  fieldConfig: GraphQLFieldConfig<any, any>,
  fieldName: string,
  typeName: string,
  schema: GraphQLSchema
) => void;

type DefaultValueIteratorFn = (
  type: GraphQLInputType,
  defaultValue: any
) => any;

import { forEachField, forEachDefaultValue } from "@graphql-tools/utils";

// Analyze all fields in schema
forEachField(schema, (fieldConfig, fieldName, typeName) => {
  if (!fieldConfig.resolve) {
    console.log(`Field ${typeName}.${fieldName} has no custom resolver`);
  }
  
  // Check for deprecated fields
  if (fieldConfig.deprecationReason) {
    console.log(`Deprecated field: ${typeName}.${fieldName}`);
  }
});

// Process default values
forEachDefaultValue(schema, (type, defaultValue) => {
  console.log(`Default value found:`, defaultValue);
  return defaultValue; // Return processed value
});

/**
 * Append fields to a GraphQL object type
 * @param type - The object type to modify
 * @param newFields - Fields to append
 * @returns New object type with appended fields
 */
function appendObjectFields(
  type: GraphQLObjectType,
  newFields: GraphQLFieldConfigMap<any, any>
): GraphQLObjectType;

/**
 * Remove fields from a GraphQL object type
 * @param type - The object type to modify
 * @param testFn - Function to test which fields to remove
 * @returns New object type with fields removed
 */
function removeObjectFields(
  type: GraphQLObjectType,
  testFn: (fieldName: string, fieldConfig: GraphQLFieldConfig<any, any>) => boolean
): GraphQLObjectType;

/**
 * Select specific fields from a GraphQL object type
 * @param type - The object type to modify
 * @param fieldNames - Names of fields to keep
 * @returns New object type with only selected fields
 */
function selectObjectFields(
  type: GraphQLObjectType,
  fieldNames: string[]
): GraphQLObjectType;

/**
 * Modify fields of a GraphQL object type
 * @param type - The object type to modify
 * @param fn - Function to modify each field
 * @returns New object type with modified fields
 */
function modifyObjectFields(
  type: GraphQLObjectType,
  fn: (
    fieldConfig: GraphQLFieldConfig<any, any>,
    fieldName: string
  ) => GraphQLFieldConfig<any, any> | [string, GraphQLFieldConfig<any, any>] | null | undefined
): GraphQLObjectType;

import { 
  appendObjectFields, 
  removeObjectFields, 
  selectObjectFields, 
  modifyObjectFields 
} from "@graphql-tools/utils";
import { GraphQLString } from "graphql";

// Append new fields
const userTypeWithEmail = appendObjectFields(userType, {
  email: {
    type: GraphQLString,
    description: 'User email address'
  }
});

// Remove deprecated fields
const cleanUserType = removeObjectFields(userType, (fieldName, fieldConfig) => {
  return !!fieldConfig.deprecationReason;
});

// Select only specific fields
const publicUserType = selectObjectFields(userType, ['id', 'name', 'avatar']);

// Modify all fields
const userTypeWithLogging = modifyObjectFields(userType, (fieldConfig, fieldName) => {
  const originalResolve = fieldConfig.resolve;
  return {
    ...fieldConfig,
    resolve: (source, args, context, info) => {
      console.log(`Resolving User.${fieldName}`);
      return originalResolve ? originalResolve(source, args, context, info) : source[fieldName];
    }
  };
});

/**
 * Convert a GraphQL field to a field configuration
 * @param field - The field to convert
 * @param type - The parent type
 * @param schema - The schema context
 * @returns Field configuration object
 */
function fieldToFieldConfig(
  field: GraphQLField<any, any>,
  type: GraphQLObjectType | GraphQLInterfaceType,
  schema: GraphQLSchema
): GraphQLFieldConfig<any, any>;

/**
 * Convert a GraphQL argument to an argument configuration
 * @param argument - The argument to convert
 * @returns Argument configuration object
 */
function argumentToArgumentConfig(
  argument: GraphQLArgument
): GraphQLArgumentConfig;

/**
 * Get all object types that implement a given abstract type
 * @param abstractType - The interface or union type
 * @param schema - The GraphQL schema
 * @returns Array of implementing object types
 */
function getImplementingTypes(
  abstractType: GraphQLAbstractType,
  schema: GraphQLSchema
): GraphQLObjectType[];

/**
 * Check if a type implements an abstract type
 * @param schema - The GraphQL schema
 * @param maybeType - The type to check
 * @param superType - The abstract type to check against
 * @returns True if the type implements the abstract type
 */
function implementsAbstractType(
  schema: GraphQLSchema,
  maybeType: GraphQLType,
  superType: GraphQLAbstractType
): boolean;

import { getImplementingTypes, implementsAbstractType } from "@graphql-tools/utils";

// Find all types implementing an interface
const nodeInterface = schema.getType('Node') as GraphQLInterfaceType;
const implementingTypes = getImplementingTypes(nodeInterface, schema);
console.log('Types implementing Node:', implementingTypes.map(type => type.name));

// Check if a specific type implements an interface
const userType = schema.getType('User') as GraphQLObjectType;
const implementsNode = implementsAbstractType(schema, userType, nodeInterface);
console.log('User implements Node:', implementsNode);

// Get all types in a union
const searchResultUnion = schema.getType('SearchResult') as GraphQLUnionType;
const unionTypes = getImplementingTypes(searchResultUnion, schema);
console.log('Union member types:', unionTypes.map(type => type.name));

/**
 * Add a path segment to a response path
 * @param prev - Previous path segment
 * @param key - Key to add to path
 * @param typename - Type name for the path segment
 * @returns New path with added segment
 */
function addPath(prev: ResponsePath | undefined, key: string | number, typename?: string): ResponsePath;

/**
 * Convert a response path to an array representation
 * @param path - The response path to convert
 * @returns Array representation of the path
 */
function pathToArray(path: ResponsePath): Array<string | number>;

interface ResponsePath {
  readonly prev: ResponsePath | undefined;
  readonly key: string | number;
  readonly typename?: string;
}

/**
 * Parse a selection set from a string
 * @param selectionSet - String representation of selection set
 * @returns Parsed selection set node
 */
function parseSelectionSet(selectionSet: string): SelectionSetNode;

/**
 * Check if a type contains a specific selection set
 * @param schema - The GraphQL schema
 * @param type - The type to check
 * @param selectionSet - The selection set to check for
 * @returns True if the type can satisfy the selection set
 */
function typeContainsSelectionSet(
  schema: GraphQLSchema,
  type: GraphQLCompositeType,
  selectionSet: SelectionSetNode
): boolean;

import { parseSelectionSet, typeContainsSelectionSet } from "@graphql-tools/utils";

// Parse selection set from string
const selectionSet = parseSelectionSet(`{
  id
  name
  posts {
    title
    content
  }
}`);

// Check if type supports selection
const userType = schema.getType('User') as GraphQLObjectType;
const canResolve = typeContainsSelectionSet(schema, userType, selectionSet);
console.log('User type can resolve selection:', canResolve);